Some web services, like password managers with cloud access (or bank accounts, as another example), require re-entry of your password as a security measure if you've closed and/or re-opened the browser tabs/windows. I want this as an option for Proton.me, e.g. a toggle in security settings. I realize having to re-enter your password every time you re-open the tab(s)/window(s) might seem like an inconvenience, but for those using a password manager, it's practically a non-issue.

(Note: I'm aware there's an option on the login screen that is sorta similar to this topic, but it doesn't have the same effect.)